攝影筆記─有關分辨 Nikon 鏡頭 AI 及 AI-S的文章

non-AI,AI,AIS鏡之區別

另外一篇出自國外，我想直接貼上來，阿斗仔應該抓不到吧。
 

An MF AI-S type lens is best recognized by its LENS TYPE SIGNAL NOTCH - the little milled notch next to the lens locking indentation (see illustration). This indicates that the aperture stop down action is standardized as opposed to pre-AI-S lenses. 

A standardized aperture stop down action is a requirement for getting reliable shutter speeds in P and S modes, where the aperture is generally controlled by the aperture stop down lever - and not by the aperture ring (exepted is S mode with F2 and one of the EE aperture control units which turns the aperture ring automatically via either the METER COUPLING SHOE (DS-1 and DS-2) or the EE SERVO COUPLING POST (DS-12)).  An MF AI-S type lens can tell a few cameras (FA, F-501 & F4) its focal length on a very crude scale; either less than (<) 135 mm or equal to or greater than (>=) 135 mm. This is done via the FOCAL LENGTH INDEXING RIDGE (present on lenses >= 135 mm). MANUAL FOCUS Nikkor Resources | Autofocus Nikkor Resources

NIKKOR 20mm 1:2.8 (AI-S)

The information is used in dual program of FA and F-501 to optimize the shutter speed so as to minimize the effect of camera movement. An MF AI-S type lens has an orange smallest aperture number (highest f/number) on the ADR row - NOT just on the normal aperture number row as some lenses happen to have (AI 16/2.8 e.g.). Be aware that new aperture rings (even with orange smallest ADR aperture number) can have been retro fitted. 

An AI-S type Tele Converter will relay the MAXIMUM APERTURE INDEXING POST (see illus.) of an AI-S type lens (or an AI lens). The so called AI type TC will not do this. An AI-S type TC will also relay the prescence of the LENS TYPE SIGNAL NOTCH of an AI-S type lens so the combination will function as an AI-S type lens by itself. 

AI-S type lenses and TCs do infact AI-couple to AI-coupled finders and cameras via the METER COUPLING RIDGE (see illus.) It is NOT possible to easily "AI-S modify" an AI or pre-AI lens since the major difference is internal - the nature of the stop down action! 

Only a few cameras will take advantage of the extra features. Four cameras will distinguish between an AI and an MF AI-S type lens; FA, F-301, F-501 & F4 but FG will take advantage of AI-S type lenses even though it will NOT recognize them (see below).